In recent years, electronic data forensics has played an important role in the detection of cases. Because the electronic data have the characteristics of vulnerability, in order to finally analyze the useful evidence, it is necessary for the forensics personnel to have professional electronic forensics technology and methods to ensure the authenticity and objectivity of the cases. Three kinds of forensic techniques are analyzed in detail:electronic forensics based on Windows, electronic forensics based on smart phones, and electronic forensics based on network. Electronic forensics based on smart phones, include Android mobile phone and iPhone mobile phone. And the future development direction of electronic forensics technology is put forward as well.